Using TortoiseSVN (module TortoiseMerge) as unprivileged user (only
member of Users group, no other permissions granted) on Windows XP
Professional client exposes something that looks like a bug in the
TortoiseMerge module.

When trying to merge branch in which a new folder was added with
original folder (trunk) creates the folder in trunk, correctly marks it
for adding, but then aborts with error "Can't open 'tmp': Access is
denied.". After error, trunk can be restored to original (HEAD) state
using revert from repository.

At the time of writing no similar bugs were documented issue tracker and
no fixes that might resolve tis issue were noted in Changelog.txt in
TortoiseSVN trunk.

My guess is that the file or folder "tmp" should have been created
either in user %TEMP% folder or somewhere in working copy. Unfortunately
I don't know TortoiseSVN code good enough to give anything more than a
guess.

Oh, and more thing: I'm only sending this to list, without expecting
direct answer. I will watch list archives if there will be any request
for more information or better explanation, but I don't expect and don't
like direct answers. For this reason my return address is invalid and
replies sent directly to me will bounce.